I bought a ML350CDI Grand Edition from new in Sept 2011 from Mercedes Benz Brooklands in the UK. From the very beginning, about 40% of the time when I drive the car from a cold or standing start, within a short distance, say 200 yards, it seems to hesitate, almost as if it is ‘thinking’ about which gear to choose / engage and then suddenly and violently lurches forward, sometimes with an audible thud . The best way to describe this is feels like it has been given a kick up the backside! It will do this a few times before it eventually settles down. The first 2 times I took it back to Mercedes Brooklands they did not accept that there was a problem, said they could not replicate it and I had to take it back. On the 3rd occasion they initially said there was no problem initially they implied it was user error but as I pointed out my car is driven by other people all of whom have experienced this fault, so they asked me to come into the showroom to replicate the problem for them. So I drove the car with a mechanic beside me and when the issue occurred he accepted that there was a problem but said it's not as I had described it – he said ‘it feels like a gear box issue not a miss-fire’. Brooklands continued to struggle to diagnose and fix the problem themselves so eventually they involved Mercedes Germany. After nearly 3 weeks, they eventually updated the software, replaced solenoids and gave me the car back apparently all fixed. Within a few days the issue recurred so the car went back a 4th time again they struggled to replicate the issue and gave the car back to me as is. The car is now with Mercedes for the 5th time for the same issue and they want me to go back and replicate the problem for them once again because in their opinion there is no issue and the car and 'substantially behaves in accordance with accepted parameters’. Anyone else had this issue or got any suggestions?

You havent said what year your ML is but Im guessing 2009/2010 model year.

This sounds like a classic valve body fault to me. Could you find out exactly what has been replaced and whether you have had a valve body fitted? Looking at the shift adaptation data on STAR would be a big clue as to what is going on shift wise.

Without driving the car and having access to data and previous fixes etc it will be very difficult to say but the 7Gtronic gearbox is having more and more problems with valve bodies and electroplates.